Commercial aircraft typically employ an environmental control system to pressurize a passenger cabin of the aircraft and/or thermal anti-icing systems to provide heated air for anti-icing applications. Air supply to these systems is typically provided by bleed air extracted from a compressor of an aircraft engine. To meet pressure and/or temperature demands of the various aircraft systems, bleed air is often extracted from a higher stage of the compressor that provides bleed air having a pressure and/or temperature above that demanded by the various systems. For example, bleed air is often extracted from a mid-stage of a high pressure compressor of an aircraft engine. The pressurized bleed air is often cooled, via a precooler, and reduced in pressure, via a pressure regulating valve, prior to providing the bleed air to a system (e.g., an environmental control system) of the aircraft. Thus, much of the energy spent by the engine to produce the bleed air is wasted when cooling the bleed air via the precooler and reducing the pressure of the bleed air. Extracting high-pressure bleed air from the mid-stage of the high pressure compressor of the aircraft engine may reduce the efficiency of the engine.
Some known piston engines provide pressurized air for the cabin environmental control system with a shaft-driven compressor, typically known as a supercharger. Known shaft-driven superchargers typically receive ambient air from an atmospheric inlet. Such shaft-driven superchargers pressurize the ambient air prior to supplying the various aircraft systems. However, the atmospheric inlet of such a supercharger produces drag. Additionally, the atmospheric inlet is often susceptible to icing and, thus, typically requires an anti-icing system that increases costs and system complexity. Further, known shaft-driven superchargers may have to be relatively large to produce a pressure change sufficient to power the systems of an aircraft. Other known systems employ a turbo-compressor. However, similar to the shaft-driven supercharger mentioned above, these known turbo-compressors also pressurize ambient air and, thus, suffer from the above-identified drawbacks.